1. Field of the Invention
This invention belongs to the technical field of a semiconductor substrate, a display panel, or a display device, formed by using SOI (silicon on insulator) technology.
2. Description of the Related Art
The market of liquid crystal displays using thin film transistors has been expanded. Thin film transistors are one kind of field effect transistors and are so called because semiconductors that form channels are formed of thin films. Ideally, it would be good if thin film transistors whose channels are formed of single crystal semiconductors could be manufactured; however, amorphous silicon thin films or polycrystalline thin films which can be manufactured at a process temperature of 600° C. or lower are used for the thin film transistors because glass substrates which are to be base materials of liquid crystal displays have a low temperature limit.
Of course, a technique for forming a single crystal silicon thin film over an insulating substrate which can be used for a liquid crystal display device has been developed. For example, a technique for forming a single crystal silicon thin film over a crystallized glass substrate which is a high heat-resistant glass is disclosed (see Patent Document 1: Japanese Published Patent Application No. H11-163363, Patent Document 2: Japanese Published Patent Application No. 2000-012864, and Patent Document 3: Japanese Published Patent Application No. 2000-150905). In recent, a technique for making small pieces of single crystal silicon into a tiled pattern over a glass substrate is disclosed as an SOI substrate for an active matrix liquid crystal display (see Patent Document 4: Japanese Translation of PCT International Application No. 2005-539259).